Results from a new study suggest that measuring the brain’s neural response to pain using functional magnetic resonance imaging (FMRI) may be useful in the evaluation of the effectiveness of new pain medications. The tool could provide the objective evidence needed to prevent the premature discounting of potentially useful therapeutic approaches, according to the researchers from the Nuffield Division of Anaesthetics, University of Oxford, UK. Lead author Vishvarani Wanigasekera, MD, commented, “Many potential pain relieving drugs identified in preclinical research fail to reach the market because of a lack of early objective evidence that shows whether a drug is effectively reaching target pain receptors in the body and regulating chronic pain mechanisms.” The results are published in the journal Anesthesiology.

At present, the usual measure of efficacy used in drug development is patient reported degree of pain relief, which can be both subjective and context-dependent. Since early development studies typically involve a small sample size, this subjectivity can cause researchers to pass over compounds that might be effective in larger populations. In this study, using topical capsaicin to induce the characteristics of neuropathic pain, the team administered either gabapentin, ibuprofen, or placebo and assessed the impact on the brain’s neural response to pain using FMRI. Pain related neural activity was significantly reduced in the subjects who received gabapentin, even with extremely low subject numbers, highlighting the potential for FMRI to make a drug’s effect clear in small cohorts.